A mobile device is able to connect to a wireless access network to perform various different types of communications, such as to establish a call with another endpoint, to access websites, to perform text messaging, and so forth. To perform communications, data units are sent between the mobile device and a node (e.g. base station) in the wireless access network.
With some wireless protocols, an acknowledged mode of operation can be provided, in which a receiver (one of the mobile device and the wireless access network node) can send an acknowledgement of receipt of a data unit to a transmitter (the other of the mobile device and the wireless access network node) that sent the data unit for reliable communication. Use of an acknowledged mode of operation allows for selective retransmission of data units that have not been correctly received or decoded by the receiver.